Molecular Simulation Analysis of Polyurethane Molecular Structure under External Electric Field

Area of Science:

• Materials Science
• Computational Chemistry
• Electromagnetics

Background:

• Polyurethane (PU) materials are crucial in power equipment.
• Understanding PU's response to electrical stress is vital for equipment reliability.

Purpose of the Study:

• To investigate the impact of external electric fields on PU molecular structure.
• To analyze microstructural and molecular energy changes in PU segments using DFT.

Main Methods:

• Combined electromagnetics and computational chemistry (DFT).
• Simulated uniform electric fields on PU hard (HS) and soft (SS) segments.
• Analyzed molecular energy, dipole moment, polarizability, and HOMO-LUMO gap.

Main Results:

• HS molecules showed decreased total energy, increased dipole moment and polarizability.
• SS molecules exhibited decreased total energy and polarizability, with a slight dipole moment increase.
• Strong electric fields caused HS molecular stretching and O-H bond cleavage; SS chains twisted without bond rupture.
• HS HOMO-LUMO gap narrowed significantly at 8.227 V/nm, indicating reduced stability.

Conclusions:

• External electric fields induce significant structural and energetic changes in PU segments.
• HS segments are more susceptible to electric field-induced degradation.
• Findings provide theoretical guidance for enhancing PU material performance in power equipment.